The present invention relates generally to agricultural harvesters and more particularly relates to root crop harvesters.
Conventional beet harvesters include a plurality of beet-conveying structures for receiving the beets from the digger lifter wheels, scrubbing and tumbling them to remove dirt and foreign material and then elevating them for delivery into a holding tank or truck moving alongside the harvester. Typically included among such conveying structures are chain, star wheel and grab roll conveyors.
Grab roll conveyors are preferred over chain or star wheel conveyors for many applications since they are more reliable and less expensive to operate and maintain. Further, in clay-type mud conditions chain conveyors are not as effective as grab roll conveyors in removing the clay that clings to the beets. Star wheel conveyors which generally do a better job of breaking up the clay often damage the beets. It would therefore be preferable to utilize a grab roll conveyor on a beet harvester whenever possible. However, when beets contaminated with clay or similar muds are processed on grab roll conveyors, the mud, weeds and beet tops that often cling to the beets collect around the bearings and bearing supports at the discharge end of the grab rolls. Consequently, the flow of the beets over the ends of the grab rolls has to be slowed and occasionally stopped to clean the foreign materials from the bearings and their supports.
A further problem encountered with grab roll conveyors arises from the flow pattern of beets between separate conveyors. Beets flow from one conveyor to the next by tumbling from the end of the first conveyor onto the front of the next conveyor. This arrangement requires substantial structural framework and reduces the compactness of the harvester. Accordingly, the harvester is often difficult to maneuver and transport, does not have its weight centered between its support wheels and can cause wheel slippage as well as side draft when towed.